Cyclic GMP (cGMP) is a molecule that acts as a secondary messenger in various biological processes. It is produced from guanosine triphosphate (GTP) by the enzyme guanylate cyclase. cGMP plays a crucial role in signaling pathways, particularly in regulating blood vessel dilation, neurotransmission, and smooth muscle relaxation. In the cardiovascular system, cGMP helps to lower blood pressure by promoting vasodilation, which is the widening of blood vessels. Additionally, it is involved in the function of certain hormones and neurotransmitters, such as nitric oxide, which stimulates its production. Overall, cGMP is essential for maintaining various physiological functions.